2 open source boards using the U4
Real designs built with the U4, from public GitHub projects: a quick way to see how others power, decouple and connect it. Each board comes with its KiCad files, full parts list and a render — and you can simulate its firmware on HardLabs.
Weather dashboard
hackclub
35.5 × 59 mm14 parts2LMIT11
Edge io ring evt0
gunnchOS3k
28 × 10 mm14 parts2LMIT0
The U4 in open source designs
The gallery holds 2 open source boards using the U4 from 2 GitHub repositories; a typical one measures about 31.8 × 34.5 mm and carries around 14 components.
100% are two-layer designs, the rest use four layers or more, and 100% carry an open source license.
The most starred is Weather dashboard by hackclub.
U4: common questions
Where can I find a U4 reference design?
Each of the 2 boards on this page is a real design using the U4. Open one to see how it is wired up, with the full BOM, a render of the layout and links to its KiCad files.
How big is a typical board using the U4?
The median is 31.8 × 34.5 mm, and 100% are two-layer designs.
What is the most popular open source board using the U4?
By GitHub stars, Weather dashboard by hackclub, with 11 stars.
Can I simulate one of these boards using the U4 before building it?
Yes. HardLabs turns a board's netlist and BOM into a working simulation, so you can boot and test firmware against it with no hardware on your desk.